1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device, which includes forming a silicon dioxide film for isolation using a solution containing a perhydrosilazane polymer.
2. Description of the Related Art
In a semiconductor device, a shallow trench isolation (STI) structure is widely used for isolation between minute devices. A process of the STI structure includes a step of forming a trench on the surface of a semiconductor substrate, and a step of filling the trench with an insulating film. The insulating film is, for example, a silicon oxide film. As a process for forming the silicon oxide film, a CVD process using a source gas containing ozone (O3) and TEOS and a high concentration plasma (HDP) CVD process are known.
Accompanied with miniaturization of semiconductor devices, an aspect ratio of the trench becomes larger. For this reason, in the foregoing CVD process or the like, it has become difficult to form the silicon oxide film which does not generate a void and a seam in the trench. That is, it has become difficult to form the silicon dioxide film for STI having a favorable filling shape.
Hence, in the minute semiconductor devices subsequent to the 100 nm generation, a process using a coating type solution SOG (Spin-On-Grass) has been proposed (Void Free and Low Stress Shallow Trench Isolation Technology using P-SOG for sub 0.1 μm device (J. H. Heo et al., 2002 Symposium on VLSI Technology Digest of Technological Papers, pp. 132-133, 2002).
As the SOG solution, a solution (silicon hydroxide solution) obtained by dispersing silicon hydroxide (silanol, SiOH4) into an organic solvent such as alcohol is commonly used.
By applying the silicon hydroxide solution on the semiconductor substrate, a coating film of the silicon hydroxide solution is formed on the semiconductor substrate. Thereafter, the coating film is heated to generate hydrolysis and anhydration condensation reactions. In this manner, the coating film is converted into the silicon dioxide film.
In the processes of the hydrolysis and anhydration condensation reactions, a large volume shrinkage arises. As a result, a crack occurs in the silicon oxide film in the trench. That is, even by using the silicon hydroxide solution, it has become difficult to form the silicon dioxide film for STI having the favorable filling shape.
Hence, in recent years, a perhydrogenated silazane solution having a relatively few volume shrinkage among solutions of the SOG system has come to draw attention (Japanese Patent No. 3178412)
However, even the silicon dioxide film formed by using such the perhydrogenated silazane solution is not satisfactorily as a silicon dioxide film for isolation under the present circumstances.